EXPRESSION OF A NEW MR 70-KDA DYSTROPHIN-RELATED PROTEIN IN THE AXON OF PERIPHERAL-NERVES FROM TORPEDO-MARMORATA

By comparison with localizations of dystrophin family produces in rabb it peripheral nerves, we investigated the potential existence and dist ribution of similar products in peripheral nerves from Torpedo marmora ta. In immunofluorescence studies, a specific set of monoclonal antibo dies directed against dystrophin family proteins clearly stained a thi n rim surrounding each Schwann cell-axon unit both in T. marmorata and rabbit peripheral nerves. In contrast, when using the dystrophin/utro phin monoclonal H'3E7 antibody, we found a clear difference between ra bbit and T. marmorata peripheral nerves according to fluorescent label ing detected within Torpedo nerve axons. Further differences were note d following western blot analyses of T. marmorata peripheral nerve ext racts, highlighting the presence of a new and specific Mr 70-kDa prote in band belonging to the dystrophin family, which is localized within axons in addition to: (1) an Mr 400-kDa protein band detected with dys trophin/utrophin antibodies; and (2) an Mr 116-kDa doubler protein ban d corresponding to Dp116 and Up116 isoforms. All of these products, de tected according to the specificities oi the monoclonal antibodies use d, are discussed in terms of their potential identities as short and l ong dystrophin or utrophin mammalian products. Copyright (C) 1997 Else vier Science Inc.